what this recursive function does ?

Code:

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void dosomething(int a){
if (!a) return;
dosomething(a >> 0x1);
printf("%d\",(a & 0x1));

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//giving that int a is a positive number

I don't know, why don't you compile it and try it out? See what output you get for different inputs, and see if you can figure it out. If you're still stumped, post back with your best guess and explanation, and we'll help you sort out where you went wrong. Also, the string for printf looks incorrect.

There is also a missing closing brace, so the code would not even compile.

In addition to anduril's suggestion, try explaining what the individual statements and expressions do. Do you know what bit shifting and bitwise "and" achieve? If not, look them up, otherwise you will have no hope of explaining the code.

Is the printf() reachable in this code? It looks like it's set up to give a binary printing of an int, but the printf() will need to be reachable to do that.

> Is the printf() reachable in this code?
It seems like it would be a good exercise for you to do as well then :)

Quote:

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Originally Posted by Salem

> Is the printf() reachable in this code?
It seems like it would be a good exercise for you to do as well then :)

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I just did it, but I'm not entirely sure if my explanation for what I saw is correct. It does reach the printf(), but it does so only after returning (when the variable has reached 0).

The only explanation I could think of is that the function is returning you to itself (?), and that it will do this as many times as the recursion was called.

I need to get out of here, you people are trying to brainwash me with book-learn'in! :P

Quote:

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Originally Posted by Alpo

I just did it, but I'm not entirely sure if my explanation for what I saw is correct. It does reach the printf(), but it does so only after returning (when the variable has reached 0).

The only explanation I could think of is that the function is returning you to itself (?), and that it will do this as many times as the recursion was called.

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As Salem said, you need to do the exercise as well.

The point of a recursive function is that it calls itself sequentially and, when it returns, backs out sequentially. All you've described is that happens on the most deeply nested call. You also need to consider that, to return control to the (original caller) each call of the recursive function needs to return.

Quote:

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Originally Posted by Idan Damri

Code:

---

void dosomething(int a){
if (!a) return;
dosomething(a >> 0x1);
printf("%d\",(a & 0x1));

---

//giving that int a is a positive number

---

I decided it someone idea of code to test compiler optimization.

I wander what compiler does the best job optimizing it.

NOTE: I think you would need to change the input to unsigned int to get rid of undefined stuff.

Tim S.

Quote:

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Originally Posted by stahta01

NOTE: I think you would need to change the input to unsigned int to get rid of undefined stuff.

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Or assume that the supplied argument is positive. Of course, the word "assume" is a contraction of "make an ASS out of yoU and ME" when it is invalid.